Unilateral hearing loss (UHL) in school-aged children has an estimated prevalence of 1/1000 to over 5%. The prevalence of UHL in newborns is estimated to be 0.4/1000 to 3.4%. In the past, UHL was thought to have little consequence because speech and language presumably developed appropriately with one normally hearing ear. Unless they have medical problems that lead to an early hearing screen or audiogram, children with UHL are often undetected until they enter school and undergo hearing screenings. Earlier studies have suggested that a significantly increased proportion (22-59%) of children with UHL may have educational and/or behavioral problems, compared to their normally hearing peers. Limited data exists about the effect of UHL on acquisition of speech and language skills. Similarly, little is known about which children with UHL might benefit from intervention or amplification to avoid academic delay, or whether children who have early difficulties in school "catch up." The broad, long-term objective of this research is to increase the knowledge about UHL in children. The specific aims of this present study are: 1) Determine the rate of educational risk in children with UHL as compared to a control group of siblings with normal hearing, using a standardized achievement assessment;2) Determine whether educational performance or behavioral problems increase or decrease in children with UHL over time;and 3) Determine whether performance on speech-in-noise tests predicts academic achievement in children with UHL. Our primary hypothesis is that children with UHL have a 30% rate of educational risk compared with an expected 16% rate of educational risk in children with normal hearing. We defined educational risk as performance on standardized achievement tests that is 1.0 standard deviation or more below the mean. Our secondary hypotheses are: 1) Children with UHL who are at educational risk do not improve their performance in school over time;and 2) Poor performance on speech-in-noise tests is a significant risk factor for poor academic achievement in children with UHL. This study proposes a case-control study comparing children who have UHL with control siblings on standardized measures of educational and behavioral risk, using a standardized achievement assessment (WIAT-II-A) as the primary outcome measure. Assuming a 10% drop out rate, a one-tailed alpha level of 0.05 and beta level of 0.20 for 80% power, 126 subjects for each group will be recruited. Secondary outcomes will include repeating one or more grades, requiring additional educational assistance, and behavioral problems. A subgroup of children with UHL will be followed over 3 years to obtain longitudinal data about changes in achievement trajectory and behavioral problems. Speech-in-noise test performance will be obtained through an audiologic protocol developed for this study. Bivariate and multivariable analyses will be used to determine which socioeconomic, clinical or patient factors are independently associated with our outcomes. The results from this study will enlighten the epidemiologic and clinical impact UHL has on a student's educational achievement.